JP6359082B2 - Recycle parts that have been layered - Google Patents

Description

[Cross-reference of related applications]
This application claims priority to US Provisional Application No. 61 / 813,871, filed Apr. 19, 2013, entitled “Method For Forming Single Crystal Parts Using Additive Manufacturing And Remelt”. Is incorporated herein by reference in its entirety.

  This embodiment relates generally to the field of additive manufacturing, and more particularly to repairing defects in additively manufactured parts.

  Layered modeling is a process that can be created by a machine that creates each layer, one layer at a time, according to a three-dimensional (3D) computer model of the part. In powder bed additive manufacturing, a layer of powder is spread on a platform and selected areas are joined by sintering or melting with a directed energy beam. The platform is indexed down and another layer of powder is overlaid and the selected areas are similarly bonded. The process is repeated until the finished 3D part is manufactured. In direct stack additive manufacturing technology, a small amount of molten or semi-solid material is applied to the platform by extrusion, injection, or wire feed, and activated by an energy beam according to the 3D model of the part, causing the material to adhere to the part. Form. Typical additive manufacturing processes include selective laser sintering, direct laser melting, direct metal laser sintering (DMLS), electron beam melting, laser powder deposition, electron beam wire deposition, and the like.

  In additive manufacturing operations, parts are manufactured in a continuous process, eliminating features associated with traditional manufacturing processes such as machining, forging, welding, and casting, resulting in cost, material, and time savings. obtain. Moreover, additive manufacturing allows complex shaped parts to be formed relatively easily compared to conventional manufacturing processes.

  However, one problem related to additive manufacturing is quality control of the parts formed by stacking. In general, subsurface defects in parts are inherent in the additive manufacturing process. Although it can take tens of hours (or more) to stack and form a single part, nevertheless, at least some finished stacked parts, such as dirt and voids, It is inevitable to have subsurface defects. As a result, such defective items are bounced after spending considerable resources to form these parts.

  One embodiment includes a method of recycling a part. The method includes additive fabrication of a part with a shape close to a finished product and having a void volume of greater than 0 percent but less than about 15 percent. This part is encased in a shell mold. The shell mold is cured. The encased part is placed in a furnace and the part is melted. The part is solidified in the shell mold. The shell mold is removed from the solidified part.

  Another embodiment includes a method for recycling a part having an internal passage. The method includes additive fabrication of a part with a shape close to a finished product, having an internal passage, and having a volume of greater than 0 percent but less than about 15 percent void. The internal passage is filled with slurry. The slurry is cured to form a core. This part is encased in a shell mold. The shell mold is cured. The encased part is placed in a furnace and the part is melted. The part is solidified in the shell mold. The shell mold and core are removed from the solidified part.

  Further embodiments include an intermediate piece having an internal passage. The intermediate part includes a solid metal additive-molded part having a shape close to the finished product and having an internal passage. The part has more than 0 percent by volume but less than about 15 percent voids and a shape close to the finished product, with up to 15 percent extra material by volume compared to the desired finished configuration. Also included is a ceramic core disposed within the internal passage of the part and an outer ceramic shell mold enclosing the entire part such that the entire outer surface of the part is covered with the outer ceramic shell mold.

FIG. 3 is a cross-sectional view of an intermediate part with an internal passage having a core and a shell mold. It is a flowchart which shows the method for reproducing | regenerating the layered and modeled part.

  While the above figures illustrate one or more embodiments of the invention, other embodiments are also contemplated. In any case, this disclosure presents the present invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art and are within the scope and spirit of the principles of the present invention. The figures may not be drawn to scale and applications and embodiments of the present invention may include features and components not specifically shown in the figures.

  In general, this embodiment produces a layered part that has a defect (eg, a subsurface defect) to correct the defect so that the part does not need to be bounced and can be used as intended. Or provided to play. Defects in layered parts are corrected by using the part as a prototype for making a shell mold, similar to a shell mold in conventional investment casting. The part can be fully encapsulated in a shell mold, melted and then solidified to produce a substantially defect-free part of the same, potentially complex shape. Other features and benefits will be appreciated when viewed throughout the disclosure, including the attached figures.

  FIG. 1 is a schematic cross-sectional view of an intermediate part 10 that has been layered. The intermediate piece 10 can be a turbine blade that includes a blade 12, a platform 14, a root 16, and an internal passage 18. The intermediate piece 10 as shown in FIG. 1 is merely an example, provided as an example, not a limitation. The layered and shaped part 10 can be any part that can be layered and can include, for example, a fuel nozzle or turbine blade or vane. Included in the intermediate part 10 and shown in FIG. 1 are an inner core 20 and an outer shell mold 22. In an example as shown in FIG. 1, the core 20 is a ceramic core, and the shell mold 22 is a ceramic shell mold. Other core 20 and shell mold 22 materials are also contemplated.

  The intermediate part 10 is layered and shaped in a shape close to a finished product, and the wing 12, the platform 14, the base part 16, and the internal passage 18 are integrated as a part 10. However, the ceramic core 20 and the ceramic shell mold 22 are not formed as part of the component 10 during the additive manufacturing process. Component 10 includes selective laser sintering, selective laser melting, direct metal deposition, direct metal laser sintering (DMLS), direct metal laser melting, electron beam melting, electron beam wire melting, and others known in the art. Any type of additive manufacturing process that utilizes a multilayer structure, including but not limited to, can be additively manufactured. The part 10 has a shape close to that of the finished product (ie, the intermediate part 10 as shown in FIG. 1) and the desired finished configuration of the part 10 (ie, after being regenerated to substantially eliminate subsurface defects). Compared to part 10), it is layered to have up to 15 percent extra material in volume. Any extra material of the part 10 can be placed in any position where the extra material can be machined. In one example, excess material can be placed at the root 16 and / or the tip of the wing 12. Furthermore, the component 10 can be layered with a metal, such as a nickel-base superalloy, a cobalt-base superalloy, an iron-base superalloy, and mixtures thereof.

  As a result of the additive manufacturing, the component 10 may have subsurface defects. Subsurface defects can include undesirable defects such as dirt and / or voids. Voids can include, for example, holes and / or cracks. For example, part 10 may have a void volume of greater than 0 percent but less than about 15 percent by volume. In many cases, the component 10 may have more than 0 percent but less than about 1 percent void by volume, and in some cases, less than about 0.1 percent void by volume. Not. If the part 10 contains undesirable levels of voids, it may be considered unsuitable for intended use, but for many applications it may be only a small percentage by volume. Thus, the part 10 can be regenerated to correct the subsurface defects.

  As part of the process for regenerating the component 10 so that there are substantially no subsurface defects, the component 10 is made up of the ceramic core 20 and the ceramic shell mold 22 added to the component 10 after the component 10 is layered. Have In other embodiments, the component 10 may have a core 20 and a shell mold 22 of a material other than ceramic. The ceramic core 20 is formed in the internal passage 18 such that the ceramic core 20 substantially matches the shape of the internal passage 18. The ceramic core 20 can be formed by filling the internal passage 18 with a ceramic slurry, so that the volume of the internal passage 18 is occupied by the ceramic slurry. The ceramic slurry can be a ceramic commonly used as a core material for investment casting, such as silica, alumina, zircon, cobalt, mullite, kaolin, and mixtures thereof. When the internal passage 18 is filled or substantially filled with a ceramic slurry, the ceramic slurry is hardened to form a ceramic core 20 (generally solid and rigid). In other embodiments, where the part is layered and does not have an internal passage 18, the part can be regenerated to substantially repair the defect without using the ceramic core 20.

  A ceramic shell mold 22 is also added to the part 10. The ceramic shell mold 22 can envelop the entire part 10 such that the entire outer surface of the part 10 is covered by the ceramic shell mold 22 so that the ceramic shell mold 22 substantially matches the shape of the part 10. Since the part 10 has a shape close to the finished product, the intermediate part 10 serves as a prototype for making the ceramic shell mold 22. The ceramic shell mold 22 immerses the entire part 10 in a ceramic slurry to form an uncured (ie, uncured) ceramic shell mold layer on the entire part 10 to thereby form the part 10. Can be formed to wrap. The layer is dried and the part is repeatedly dipped and dried as many times as necessary to form a sufficiently thick uncured ceramic shell mold. The thickness of the uncured ceramic shell mold can range from about 5 mm to about 32 mm. The uncured ceramic shell mold is then cured to form a ceramic shell mold 22 (generally having solid and rigid properties). The ceramic slurry, and thus the ceramic shell mold 22, can be, for example, silica, alumina, zircon, cobalt, mullite, kaolin, and mixtures thereof. Alternatively, in one example, the ceramic shell mold 22 and the ceramic core 20 can be formed simultaneously such that the ceramic shell mold 22 wraps the entire outer surface of the component 10 and the ceramic core 20 wraps the entire surface of the internal passage 18.

  FIG. 2 is a flowchart illustrating an embodiment of a method 30 for regenerating a layered component. The method 30 can be used to repair a subsurface defective part 10 so that the part 10 can be used as desired and does not need to be rebounded.

  First, the intermediate part 10, which may optionally include the internal passage 18, is layered to a shape close to the finished product (step 32). Including, but not limited to, selective laser sintering, selective laser melting, direct metal deposition, direct metal laser sintering, direct metal laser melting, electron beam melting, electron beam wire melting, and others known in the art Any type of additive manufacturing process, which is not limited, can be used to additively mold the part 10. Furthermore, the component 10 can be layered as a metal such as a nickel-base superalloy, a cobalt-base superalloy, an iron-base superalloy, and mixtures thereof. The layered shaped part 10 has an undesirable defect that can have more than 0 percent but less than about 15 percent voids (eg, holes and / or cracks) in volume (other Undesirable defects may include dirt). In one embodiment, part 10 may have undesirable voids that are greater than 0 percent by volume, but less than about 1 percent, and even less than about 0.1 percent by volume. Moreover, the part 10 can be layered to have up to 15 percent extra material in volume compared to the desired finished configuration in a shape close to the finished product. This means that the stacked and formed parts 10 may contain extra material beyond what is needed to form the desired finished configuration. This extra material can be placed on the part 10 at any location where the extra material can be machined. In one example, excess material can be placed at the root 16 and / or the tip of the wing 12, such as a separate gate position. In one embodiment, the component 10 is additively shaped to intentionally include a hollow portion (eg, a hollow portion resembling a hole of a desired size, shape, etc.) to save time in the additive manufacturing process. .

  Next, if at least one internal passage 18 is present, it can be filled with a ceramic slurry or other suitable core material (step 34). Filling the internal passage 18 with the slurry results in the volume of the internal passage 18 being occupied by the slurry. Each internal passage 18 can be filled with slurry. The slurry can be a ceramic material commonly used as a core material in conventional casting processes, including but not limited to silica, alumina, zircon, cobalt, mullite, and kaolin.

  When the internal passage 18 is filled with the ceramic slurry, the ceramic slurry is cured to form the inner core 20 (step 36). The slurry can be cured in situ within the component 10 by a suitable heat treatment. The core 20 occupies the internal passage 18 such that the core 20 substantially matches the shape of the internal passage 18 of the component 10. Steps 34 and 36 can be omitted if the internal passage 18 is not present.

  The part 10 is then wrapped in an uncured (uncured) shell mold (step 38). The uncured shell mold envelops the entire part 10 so that the entire outer surface of the part 10 is covered by the uncured shell mold so that the uncured shell mold substantially matches the shape of the part 10. (I.e., substantially seal the component 10). There may be situations where the core 20 is at or near the outer surface of the component 10 and the core 20 forms part of the shell mold 22 resulting in a gap in the shell mold 22 above the portion of the core 20. . The uncured shell mold can be formed to wrap the part 10 by immersing the entire part 10 in a ceramic slurry to form a layer of uncured ceramic shell mold on the entire part 10. The layer is dried and the part is repeatedly dipped and dried as many times as necessary to form a sufficiently thick uncured shell mold. As an alternative to immersing the part 10 in the ceramic slurry, the ceramic slurry can be dried over the part 10 and dried. The acceptable thickness of the uncured shell mold can range from about 5 mm to about 32 mm. The uncured shell mold can be heated at an intermediate temperature to partially sinter the ceramic and heat off any binder in the uncured shell mold.

  The uncured shell mold is then cured to form the outer shell mold 22 (step 40). The shell mold 22 can be, for example, silica, alumina, zircon, cobalt, mullite, kaolin, and mixtures thereof. The ceramic shell mold 22 is cured at a temperature in the range of about 649 ° C. (1200 ° F.) to about 982 ° C. (1800 ° F.) for about 10 to about 120 minutes to form the ceramic shell mold 22. Can be cured to full density. Since the uncured ceramic shell mold envelops the entire part 10 and substantially matches the shape of the part 10, the part 10 serves as a prototype in the ceramic shell mold 22 (used in conventional investment casting processes). Play)

  Next, the undesirably defective part 10 is melted in a ceramic shell mold 22 now having a prototype of the part 10 (step 42). One way to melt the part 10 in the ceramic shell mold 22 is to place at least a portion of the part 10 in a furnace. However, other means of applying heat so that the part 10 is melted in the ceramic shell mold 22 can be used. For example, a double chill block and furnace assembly can be used. The material from which the part 10 is made generally has a melting point that is lower than the melting point of the material forming the core 20 and shell mold 22. This allows the component 10 to melt inside the ceramic shell mold 20 without contaminating the material of the component 10 with the material of the ceramic core 20 and / or the ceramic shell mold 22. Melting the part 10 in the ceramic shell mold 22 causes the material of the part 10 to become dense with the aid of gravity or other means to substantially remove unwanted voids originally present in the part 10. to enable. If part 10 is layered to have up to 15% extra material by volume, this extra material is also melted to fill the holes and / or cracks in part 10 (so that the part The extra material filling the holes and / or cracks in 10 no longer exists where it was originally). Melting the part 10 in the shell mold 22 can also help remove dirt from the part 10, which is generally easier to dissolve in the liquid part 10 than in the solid part 10.

  After the part 10 is melted inside the ceramic shell mold 22, the part 10 is solidified in the ceramic shell mold 22 (step 44). The part 10 can be solidified using a chill block or any other means that cools the part 10 to a temperature at which the part 10 can be solidified. The part 10 solidified in the ceramic shell mold 22 forms the part 10 in the same shape as the part 10 that was originally layered, but now the part 10 has increased density and reduced voids and other defects? Or substantially removed (ie, in the desired finished configuration). If the part 10 is directional solidified using a starter seed or particle selector, then the dirt in the part 10 is pushed or collected by the solidification interface into a common area of the part 10 and thereafter Can be removed and discarded.

  Finally, the ceramic core 20 and the ceramic shell mold 22 are removed from the solidified part 10 (step 46). For example, the ceramic core 20 can be etched out or removed by caustic leaching, and the ceramic shell mold 22 can be struck and broken. The finished part 10 is inspected to ensure that undesirable defects such as voids are reduced or substantially eliminated and that the finished part 10 has the same shape as the layered part 10. You can also The method 30 can then be repeated as necessary.

  If the part is layered and does not have an internal passage 18, the part can be regenerated to substantially repair subsurface defects similar to those described for method 30. However, because there is no internal passage 18, steps 34 and 36 need not be performed.

[Description of possible embodiments]
The following is a non-exclusive description of possible embodiments of the invention.

  A method for reclaiming a part, wherein the part is additively shaped to have a shape close to a finished product and having a volume greater than 0 percent but less than about 15 percent void; Wrapping the shell mold; curing the shell mold; placing the wrapped part in a furnace to melt the part; solidifying the part in the shell mold; and removing the shell mold from the solidified part ;including.

The method of the preceding paragraph may optionally include, as an addition and / or alternative, any one or more of the following techniques, steps, features and / or configurations:
The part is layered to have a void volume of greater than 0 percent but less than about 1 percent.

  The part is layered with a shape close to the finished product and up to 15 percent extra material in volume compared to the desired finished configuration.

  The part is a blade or vane and by volume up to 15 percent extra material is placed at the root of the part or the tip of the wing.

  Wrapping the part with a shell mold includes wrapping the whole part with the shell mold so that the entire outer surface of the part is covered by the shell mold.

  Wrapping the part in a shell mold includes: (a) immersing the entire part in a slurry to form a shell mold layer over the entire part; (b) drying the shell mold layer; c) repeating steps (a) and (b) until an acceptable shell mold thickness is formed to envelop the entire part.

  The component is layered using at least one of selective laser sintering, selective laser melting, direct metal deposition, direct metal laser sintering, direct metal laser melting, and electron beam melting.

  The component is layered to be of a metal selected from the group consisting of nickel-base superalloy, cobalt-base superalloy, iron-base superalloy, and mixtures thereof.

  A method of reclaiming a part having an internal passage, wherein the part has a shape close to a finished product, has an internal passage, and has a volume of more than 0 percent but less than about 15 percent void. Additive manufacturing; filling internal passages with slurry; curing slurry to form core; wrapping parts with shell mold; curing shell mold; putting encased parts into furnace Melting the part; solidifying the part in a shell mold; and removing the shell mold and core from the solidified part.

The method of the preceding paragraph may optionally include, as an addition and / or alternative, any one or more of the following techniques, steps, features and / or configurations:
The core substantially matches the shape of the internal passage of the part, and the shell mold substantially matches the shape of the part.

  The part is layered to have a void volume of greater than 0 percent but less than about 1 percent.

  The part is layered with a shape close to the finished product and up to 15 percent extra material in volume compared to the desired finished configuration.

  The part is a blade or vane and by volume up to 15 percent extra material is placed at the root of the part or the tip of the wing.

  The component is layered using at least one of selective laser sintering, selective laser melting, direct metal deposition, direct metal laser sintering, direct metal laser melting, and electron beam melting.

  The component is layered to be of a metal selected from the group consisting of nickel-base superalloy, cobalt-base superalloy, iron-base superalloy, and mixtures thereof.

  The slurry is selected from the group consisting of silica, alumina, zircon, cobalt, mullite, and kaolin.

  The shell mold is selected from the group consisting of silica, alumina, zircon, cobalt, mullite, kaolin and mixtures thereof.

  Encapsulating the part with the shell mold includes wrapping the entire part with the shell mold so that the entire outer surface of the part is wrapped with the shell mold.

  Wrapping the part in a shell mold includes (a) immersing the entire part in a slurry to form a layer of the shell mold over the entire part, (b) drying the layer of the shell mold, and ( c) repeating steps (a) and (b) until an acceptable shell mold thickness is formed to envelop the entire part.

  An intermediate part with an internal passage, which is a solid metal layered part with an internal passage in a shape close to the finished product, the part being greater than 0 percent in capacity A solid metal additive-molded part having less than about 15 percent voids, and a shape close to the finished product, with up to 15 percent extra material in volume compared to the desired finished configuration; A ceramic core disposed within the interior passage; and an outer ceramic shell mold enclosing the entire part such that the entire outer surface of the part is encased in the outer ceramic shell mold.

  Any relative or degree terms used herein, such as “generally”, “substantially”, “about”, and the like, are defined by any applicable definition or It should be interpreted and subject to restrictions. In any case, any relative or degree word used herein is a variation of normal manufacturing tolerances, accidental placement variations, temporary placement or shape variations caused by operating conditions, Any and all disclosed embodiments as well as ranges or variations as would be understood by one of ordinary skill in the art in view of the entirety of the present disclosure, etc. It is.

  Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes in form and detail may be made without departing from the spirit and scope of the invention.

Claims (19)

A method for recycling a part, the method comprising:
In near net shape, by volume, 0 is greater than percent by lamination molding parts so as to have a void of less than 1 5 percent,
Wrapping the part in a shell mold,
Curing the shell mold;
Placing the encased parts in a furnace and melting the parts;
Letting again solidify the melt within the shell mold,
Removing the shell mold from the solidified part;
A method for recycling a part, including: The method of claim 1, wherein the part is layered to have a void volume of greater than 0 percent but less than 1 percent. The method of claim 1, wherein the part is layered in the near net shape to have up to 15 percent extra material in volume compared to the desired finished configuration.   The method of claim 3, wherein the part is a blade or vane and, by volume, the up to 15 percent extra material is placed at the root of the part or at the tip of a wing.   The method of claim 1, wherein wrapping the part with a shell mold comprises wrapping the entire part with the shell mold such that the entire outer surface of the part is covered by the shell mold. Wrapping the part in the shell mold,
(A) immersing the whole of the part in a slurry to form a layer of the shell mold on the whole of the part;
(B) drying the layer of the shell mold;
(C) repeating steps (a) and (b) until an acceptable shell mold thickness is formed to wrap the whole of the part;
The method of Claim 5 including the process of these.   The component is layered using at least one of selective laser sintering, selective laser melting, direct metal deposition, direct metal laser sintering, direct metal laser melting, and electron beam melting; The method of claim 1.   8. The method of claim 7, wherein the component is layered to be of a metal selected from the group consisting of nickel-base superalloy, cobalt-base superalloy, iron-base superalloy, and mixtures thereof. A method of reclaiming a part having an internal passage, the method comprising:
In near-net-shape, has an internal passage, by volume, 0 is greater than percent by lamination molding the component so as to have a void of less than 1 5 percent,
Filling the internal passage with slurry;
Curing the slurry to form a core;
Wrapping the part in a shell mold,
Curing the shell mold;
Placing the encased parts in a furnace and melting the parts;
Letting again solidify the melt within the shell mold,
Removing the shell mold and core from the solidified part;
A method of recycling a part having an internal passage. Said core, it conforms to the shape of the internal passage of the previous SL components, and the shell mold, which conforms to the shape of the prior SL component, The method of claim 9. The method of claim 9, wherein the part is layered to have a void volume of greater than 0 percent but less than 1 percent. 10. The method of claim 9, wherein the part is layered to have up to 15 percent extra material in volume compared to the desired finished configuration in the near net shape .   The method of claim 12, wherein the part is a blade or vane and, by volume, up to 15 percent of excess material is placed at the root of the part or the tip of a wing.   The component is layered using at least one of selective laser sintering, selective laser melting, direct metal deposition, direct metal laser sintering, direct metal laser melting, and electron beam melting; The method of claim 9.   15. The method of claim 14, wherein the component is layered to be of a metal selected from the group consisting of nickel-base superalloy, cobalt-base superalloy, iron-base superalloy, and mixtures thereof.   The method of claim 9, wherein the slurry is selected from the group consisting of silica, alumina, zircon, cobalt, mullite, and kaolin.   The method of claim 9, wherein the shell mold is selected from the group consisting of silica, alumina, zircon, cobalt, mullite, kaolin and mixtures thereof.   The method of claim 9, wherein wrapping the part with a shell mold comprises wrapping the entire part with the shell mold such that an entire outer surface of the part is covered by the shell mold. Wrapping the part with a shell mold,
(A) immersing the whole of the part in a slurry to form a layer of the shell mold on the whole of the part;
(B) drying the layer of the shell mold;
(C) repeating steps (a) and (b) until an acceptable shell mold thickness is formed to wrap the whole of the part;
The method according to claim 18, comprising the steps of:

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